[Pgpool-general] Help in pgpool loadbalancing

[Steven Crandell]

Again, I'm fairly new to pgpool, so please take just about anyone's advice
over mine but I believe you'll want to run pcp_detach_node for the node in
question while you vacuum

On Mon, Jul 20, 2009 at 4:19 AM, Nimesh Satam <nimesh.satam at gmail.com>wrote:

> Glyn/Steven,
>
>
> Thanks for your reply.
>
> What we are trying to do here is: when we are doing a database vacuum we
> don't want any connections for the given node. It might be any of the nodes
> in the replication.
>
> Over the weekend when we tried to change the weight of the backend-1 to 0
> and reload using the pgpool reload facility the node was still receiving
> connections. Hence I am not sure if what I am trying to do is correct or
> not.
>
> Can you tell me how I can achieve this? I just want to make sure that we do
> not send any Select queries to a certain node for a certain period of time.
>
> Regards,
> Nimesh.
>
>
> On Mon, Jul 20, 2009 at 1:33 AM, Steven Crandell <
> steven.crandell at gmail.com> wrote:
>
>> As far as I understand things, you would still be seeing
>> inserts/updates/deletes on backend node 0 even if it is weighted to 0
>> because pgpool considers this node to be the master and therefore the only
>> node capable of accepting new data.
>> e.g. the weight of a node in a master/slave configuration only determines
>> the number of selects being sent to slaves.
>>
>> I run a 3 node cluster with mammoth replicator replicating data from
>> master to slaves and have set up pgpool with node 0 set to weight 0 and the
>> other two slaves set to 0.5.
>>
>> My intention with this configuration is for the master to only ever
>> receive INSERT/UPDATE/DELETE statement and to have all SELECT statements
>> sent to the two slaves in a 50%/50% split.  Thereby, the cluster is able to
>> scale up to the point where the number of writes exceed the capabilities of
>> the master without wasting master system resources on reads.
>>
>> So far this setup seems to work but I must admit that this configuration
>> does not seem to be clearly documented anywhere that I could find despite it
>> being a fairly typical need for a 3rd party replication solutions.
>>
>> If my assumptions about this are wrong I hope someone with more experience
>> in this area will pipe up.
>>
>> -s
>>
>> On Sun, Jul 19, 2009 at 11:29 AM, Glyn Astill <glynastill at yahoo.co.uk>wrote:
>>
>>>
>>> > From: Nimesh Satam <nimesh.satam at gmail.com>
>>> > Subject: [Pgpool-general] Help in pgpool loadbalancing
>>> > To: pgpool-general at pgfoundry.org
>>> > Date: Sunday, 19 July, 2009, 4:04 PM
>>> > Hi,
>>> >
>>> > Can anybody highlight how queries can be loadbalanced
>>> > in pgpool? How does backend_weight0 means and what happens
>>> > if the value for this parameter is set to '0'.
>>> >
>>> > I need to use this parameter in the given below way:
>>> >
>>> >
>>> > Set backend_weight0 = 0
>>> >
>>> > So as no queries go to the first node. But in our
>>> > usage we do see queries coming to the node for whom the
>>> > parameter is set to 0. We are using pgpool in master/slave
>>> > mode, with no connection caching.
>>> >
>>> >
>>>
>>> If you do not want any queries to go through to the first node, why not
>>> just remove it completely from the config?
>>>
>>>
>>>
>>> _______________________________________________
>>> Pgpool-general mailing list
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>>>
>>
>>
>
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